1 Field of the Invention
The present invention relates to a driving circuit for driving a data line of a display device and causing pixels to be displayed with numerous gradations.
2 Description of the Related Art
In active matrix-type liquid crystal display devices, which are the dominant type of liquid crystal display device, pixels are selectively driven in pixel units (point sequence driving) or in row units (line sequence driving).
In an active matrix-type liquid crystal display device, pixels which include liquid crystal cells are arrayed in a matrix. Each pixel includes a thin film transistor (TFT) and a storage capacitance which is connected in parallel with the liquid crystal cell. The storage capacitance is provided between a drain of the TFT and a predetermined common potential, and a source of the TFT is connected to a corresponding data line.
In active matrix-type liquid crystal display devices disclosed in Japanese Patent Application Laid-open (JP-A) Nos. 2000-165244 and 2005-010276, scanning lines are sequentially selected by a gate driver, and all the TFTs connected to a selected scanning line (row) are turned on. While the TFTs of the selected row are on, gradation potentials according to display data are provided from a source driver to one end of the storage capacitance of each pixel, via data lines. Hence, the storage capacitances retain charge stored via the data lines for a frame interval.
In recent years, with increases in size of liquid crystal panels (and increases in numbers of data lines), sizes of driving circuits which are source drivers for driving the TFTs have been increasing. As a result, because wiring within the driving circuits has increased, parasitic resistances of the wiring (wiring resistances) have increased, and periods for charging the storage capacitances in the pixels to gradation voltages have become longer. Therefore, with the increase in size of liquid crystal panels of recent years, it has been becoming impossible to satisfactorily assure durations for writing to pixels in the panels.
Meanwhile, increasing the size of a chip for forming a driving circuit, in order to reduce wiring resistances, would be disadvantageous in regard to costs.